The Council of Nicaea

In 2 Nicaea, anathema was an excommunication on steroids because of the ceremony. If a council issues an anathema in regard to a matter of doctrine, it's exercising the highest form of doctrinal authority that it can. So we see that the fathers at 2 Nicaea could have aired in their historical beliefs about icon veneration or issued disciplinary canons that are no longer in force. None of them contradict any other infallible Catholic teachings.